Update README.md and CLAUDE.md to reflect all implemented features

[lienardale]

Both files were outdated, still describing the original 42 project scope
(5 shapes, 25 files, single-threaded, no tests). Updated to match the
actual codebase state:

CLAUDE.md:

• Lines of code: ~2,270 → ~6,700 (47 source files)
• Build: add debug/release/test/coverage/regression/benchmark/lint targets
• Usage: add --threads CLI options
• Controls: add H (help), I (info), 1-4 (resize), continuous input
• Project structure: full 47-file listing + tests/ tools/ gallery/ .github/
• Rendering pipeline: multi-threaded with BVH, reflections, refraction
• Shapes: 5 → 14 types (cone, disk, torus, ellipsoid, box, quadrics, CSG, mesh)
• Scene format: add extended shapes and material properties syntax
• Data structures: add t_ray, t_material, t_bvh_node, t_thread_data, enums
• Known issues: remove "no inline docs" (added), update epsilon note
• Testing: full section with unit tests, regression, benchmarks, coverage, CI/CD

README.md:

• Code stats: updated line counts and feature summary
• Controls: add H, I, 1-4 keys
• Features: add DOF, motion blur, path tracing, progressive rendering,
  anti-aliasing, gamma correction, HUD overlay
• Add Build section with make targets

https://claude.ai/code/session_01HCEjiYQXvsrx9SCAHPpok8